I admit I didn’t test AdMob recently, maybe gideros support code for AdMob needs to be updated ? Try with unity ads alone, I know it works because I released a game with unity support and latest gideros in the past month.

Ok so something is wrong here. I'm having the same issue. Managed to export my game with Admob but the moment I run the app on a device it crashes (works well on the player). I will try Unity ads as well, see how they work, but this has to be addressed sooner or later.

@unlying I used logcat and well the problem might not be what we initially thought. Did you by any chance make your project with Gideros 2017 or a version prior to it? Because if so, you may have the same problem I had. And so I may have a solution to yours.